Scene: Naked girl very visibly completely covered in blood awkwardly stumbles up to people at a campfire.
Girl at campfire: "There's something wrong with her."
Guy at campfire: "She's standing right in front of us. Completely nude. There's nothing wrong about this."
That's just a small example of how childishly unpleasant the characters and dialogue are in this movie. These characters go far beyond the usual stereotypes of dumb teenagers in horror movies, to the point where it's not funny, it's just uncomfortable because it legitimately feels like this was written by a 12 year old child shut-in who doesn't know what real people act like.
Some poor dumb kid who thought "Gee whiz, it sure would be cool to make a horror movie where the monster is a nekkid lady!", but didn't consider that movies need things like writers and effects artists and etc., and so just slapped together a movie that's almost entirely dialogue, all of which is excruciatingly bad, and padded it out with a few horribly juvenile gross-out scenes that are entirely lack any humor, and a bunch of cheap jump scares.
If you're going to make a ridiculous gross-out movie, you have to at least bring some funny writing and good effects, because otherwise what do you have? Just another piece of bargain bin trash.
